


Burning Lifeline

by Seito



Category: Katekyou Hitman Reborn!
Genre: Angst, Gen, Grief/Mourning, Hurt/Comfort, Ten Year Bazooka (Katekyou Hitman Reborn!), Ten Years Later, Time Travel
Language: English
Status: Completed
Published: 2019-12-23
Updated: 2020-01-26
Packaged: 2021-03-09 15:54:36
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 1,424
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21914923
Author URL: https://archiveofourown.org/users/Seito/pseuds/Seito
Summary: Knowledge is a sin. Ignorance is bliss. Sometimes knowing is a burden on the unwilling. What does tomorrow bring? What will you find if you open that box? Is it hope? Is it salvation? Is fear? Is it death? To know or not to know, but no matter what you choose, there is no going back.Or you could do some damage with the Ten Year Bazooka.
Relationships: Gokudera Hayato & Sawada Tsunayoshi, Hibari Kyouya & Sawada Tsunayoshi, Lambo Bovino & Sawada Tsunayoshi, Sawada Tsunayoshi & Vongola Tenth Generation Guardians, Sawada Tsunayoshi & Yamamoto Takeshi
Comments: 43
Kudos: 481





	1. Chapter 1

**Author's Note:**

> khr discord server was discussing the ten year bazooka and this popped out *amused*

The ten year bazooka was some of the best and worst technology his family ever created. 

The older he got, the more Lambo wished he could smack his younger self for being such a brat. He also blamed his parents for giving him such a powerful weapon to a reckless five year old child who had no idea what he was doing. It was so annoying to be randomly displaced, especially when Lambo didn't remember when it happened. 

Even his fifteen year old self didn't realize how lucky he was. It was all fun and games, until it wasn't. 

Lambo looked at the clock and calendar, knowing full well what today was. It was easy enough to set aside time to make sure today of all days, he wasn't disturbed. (Too easy. It was too quiet, too lonely. He would give anything to hear Tsuna wishing him good night or even Octopus Head scolding him.)

A puff of pink smoke and Lambo found him standing on the rooftop of Namimori Middle School. Just like he remembered, Levi (angry, powerful Levi who taught Lambo the finer details of Lightning Flames) stood, umbrellas drawn. Green Lightning Flames danced in the air. The Ring Battles.

He glanced to the side, breath catching in his throat as he saw _Tsuna_ (his big brother, his shelter, his rock). Lambo wanted to storm over, tell Tsuna everything, that none of this was worth it, that going down this path would seal his death. 

(Byakuran standing over Tsuna's body, the blood soaked into the ground. Hayato shoving him into a hiding hole, grabbing his Lightning Ring as Takeshi fell to Kikyo’s spear. Running, running, running, always protecting him because he was the youngest, but it wasn't fair. It wasn't FAIR because he was Tsuna's Guardian too.) 

There was no time for that. 

Instead Lambo soaked up the images of his family. 

"I didn't think I would get to see you again."


	2. Chapter 2

The ten year bazooka terrified Tsuna. 

Hayato might fanboy over the science behind it, Lambo treated like a toy, and everyone had good fun, for the most part, but it left a deep unsettling feeling in his stomach. 

It started when Hayato was the first one outside of Lambo to swap. 

A quiet afternoon of studying with Takeshi and Hayato for their upcoming test. Until Lambo had wanted to play and got upset that Tsuna couldn't. But when Lambo pulled out the ten year bazooka, Hayato was the one hit, instead of Lambo. 

And there, an older Hayato sat, dressed in a black suit and a red collared dress shirt. He looked refined, more settled into his skin than Tsuna had ever seen him before.

"This is Octopus Head?!" Lambo cried out. 

"Maa, that suit looks good on you," Takeshi said. 

Hayato merely flicked Lambo on the forehead. "Brat," he said. It lacked the usual hot tempered bite, more fond than anything else.

Hayato gave Takeshi a nod of acknowledgment before turning to look at Tsuna. 

Tsuna felt his heart skip a beat as Hayato looked at him with such _grief_. "Hayato?"

"Juudaime," Hayato said softly. There was something in his tone of voice that made Tsuna ached. 

Hayato cleared his throat. "I believe I remember this incident. We were studying for tomorrow's history test, right?" 

He smiled, and it looked so strange on him. Too gentle, too indulgent, too fond. "I'll only be here for another eight minutes, but I'll do my best to assist."

**Notes for the Chapter:**

> Happy Holidays :D
> 
> please leave a review on your way out :D


	3. Chapter 3

Takeshi was next. 

Lambo's aim was either getting better or worse. Or maybe he thought it would be funny to see the others swap instead of himself. 

But a puff of pink smoke, and ten year older Takeshi now stood in replacement. 

And the most jarring thing was the lack of smile on his face. 

"Tsuna?" Takeshi asked. His voice sounded raw, full of disbelief. 

Tsuna's words remained trapped in his throat. The very core of his soul ached in a way he couldn't describe. 

Takeshi (finally) smiled (but it was all wrong. There was no happiness in it, more false than true, a terrible mirror of the same smile that shown on Takeshi's face before he walked up to the edge of the roof). 

"Are you okay?" Tsuna blurted out. Because before he had ignored it, before he had failed Takeshi and he nearly lose Takeshi before they even got to know each other. Tsuna swore to never let his friends down again. 

Takeshi's (fake, fake, fake) smile stretched a little bit wider. "Maa, now I am." He rested his hand on Tsuna's head, ruffling his hair slightly. "Seeing you always brighten my day."

Tsuna frowned. But then why was Takeshi so sad? 

He didn't get a chance to ask before the pink smoke puffed again, and the present, younger version of Takeshi swapped back. 

Takeshi grinned, so vibrant and bright. "Hey! They come out with another Godzilla movie! That's what my future self was watching. The graphics look so cool." 

Tsuna smiled, feeling lopsided inside. "I think our latest one is still playing in theaters." 

"We should go see it! It can be our bonding thing!"


	4. Chapter 4

Objectively, Tsuna knew a lot could change in ten years. 

His five year old self dreamt about becoming a robot. His twelve year old self would have never believed he was the heir to a mafia family, much less have friends. Things changed, for better or worse. 

Absolutely nothing could have prepared him for the time Hibari got hit with the ten year bazooka. 

Everyone in the room tensed, except for Lambo who was gleefully cackling. Mukuro (newly freed and rubbing it in everyone's face) inched toward his trident and Reborn had the most shit-eating grin on his face. 

Tsuna himself braced himself because he knew Hibari would not be happy with this swap and there would be plenty of damages to repair and more than a few broken bones. 

Nothing happened. 

"Hibari-senpai?" Tsuna asked, cautiously reaching out. 

Ten year older Hibari stood, frozen staring at Tsuna. 

Tsuna summoned up his courage and took another step forward. He promised not to let his friends down and Hibari was included in that. He gently placed a hand on Hibari's arm. "What is wrong?"

Like a bow, Hibari arched downward, resting his head against Tsuna's shoulder. 

Tsuna stiffened, surprised that Hibari had willingly sought after a physical comfort. More troubling was the realization that Hibari was _trembling_. 

What broke his proudest friend to be like this? 

"I am sorry, Tsunayoshi," Hibari whispered. His voice was racked with such loathing, such pain, such grief. 

"You have nothing to apologize for," Tsuna said. He didn't know what this was about, but if forgiveness was what Hibari was seeking, then Tsuna could give him that. 

"That is why I say you're too soft, herbivore."

**Notes for the Chapter:**

> Please leave a review on your way out :D


	5. Chapter 5

Inevitable really, that Tsuna would eventually be hit with the ten year bazooka.

(He tried so hard to avoid it. One of the best things about Hyper Intuition was its built in warning system. Except, there are limits and even with all the training in the world, could Tsuna had dodged that hit from the bazooka while falling in mid air and trying to avoid hitting his mother.)

A gravestone was not what he expected to see.

Nor was the polished engraved letters of his name etched into it.

A deep numbness settled over Tsuna.

In many ways, he was not surprised. The others didn't seem to notice, not even Reborn, but the last several swaps everyone kept looking him at him with such grief.

Tsuna traced the numbers on his gravestone, memorizing the date.

“I’m going to die in less than ten years.”

It didn’t feel real. It felt too real. Tsuna didn’t know what to make of it. He was going to die. He was going to die before he even turned twenty five. Was it was a life worth living? Was it a good life? Ten years felt like an eternity; twenty four felt too young.

He honestly didn’t know what to make of it.

Pink smoke filled his vision and Tsuna found him blinking up at the familiar roof of his house.

“Pitiful Dame-Tsuna,” Reborn squeaked. “You should have been able to avoid that.”

Tsuna sat up, narrowly avoiding Reborn swinging his Leon Hammer.

“Reborn…” Tsuna said.

Reborn rolled his eyes. “Did you enjoy your trip to the future?” he asked.

He could tell the truth.

But the lie slipped out first.

Tsuna smiled. “Yeah. It looks like it’ll be an interesting time.”

**Notes for the Chapter:**

> You know this all started because the khr discord started discussing ten year bazooka lmao. 
> 
> Please leave a review on your way out :D

**Author's Note:**

> taking a closer look at Ten Year Bazooka is fascinating. I always found Lambo's line during the Ring Battles to be so horrifying because what could have happened? And then you reach the future arc. 
> 
> Please leave a review on your way :D


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